R=120;
C=33e-12;
tau=R*C;

fprintf('tau=%f ns\n',tau*1e9);
T=tau/100;
t=0:T:3*tau;
U(1)=0;
S=10;
for k=2:length(t)
U(k)=(S+(tau/T)*U(k-1))/(1+(tau/T));
end;



plot(t,U)
